During an interview with Oasis’ infamous squabbling siblings Noel and Liam Gallagher earlier this year in Chicago, the brothers were disarmingly charming – when they were separated. Vocalist Liam, who turns 24 next month, quickly got up to offer a visiting reporter strawberries from his own stash of snacks. And guitarist Noel, 29, was congenial and chatty, even when he was ordering the band’s bassist to serve tea during the interview.

But when the two got together, the brothers immediately spewed a stream of British epithets at each other quicker than most of us could utter, “Hi.”

Despite the bickering, the pair is unanimous on one thing: Oasis, which is back in town for a concert Tuesday at the Rosemont Horizon, is the world’s greatest band. They’ll concede that their idols in the Beatles might have been better than them, and that some artists (Cast, Verve, Paul Weller) come close. But for now, they are the kings.

“A lot of bands think they are (the best), but they won’t say it because they’re afraid of how they’re going to come off,” guitarist-songwriter Noel Gallagher said, lounging in a plush sofa that enveloped his small frame. “We’re just doing what we do, and if we upset a few people on the way, then, well sorry. But we don’t do it intentionally. We don’t really go out of our way to annoy people. But some people get upset by the way we just are. We speak our minds, and we do what we do. Everyone should think they’re the best, man.”

Smiling, but dead serious, he added, “We are now, anyway.”

Gallagher’s bravado isn’t without cause. Superstars in Europe, Oasis can’t burp in their native England without seeing it played up as “news” in the tabloids. But despite their brilliant debut album “Definitely Maybe” (1994), America didn’t warm up to the Manchester quintet until last winter, when “Wonderwall,” from its 1995 album “What’s the Story (Morning Glory)? ,” hit the Top 10 on the singles chart.

The band sold out almost every show they played during their U.S. tour earlier this winter, including a February date here at the Aragon (capacity 5,500). Oasis – which also includes bassist Paul “Guigsy” McGuigan, drummer Alan White and guitarist Paul “Bonehead” Arthurs – will kick off this leg of their American tour at the 13,400-seat Horizon. Their Epic labelmates the Screaming Trees and Manic Street Preachers are the openers. (Tickets are still available.)

On this U.S. tour, the musicians will play to approximately 225,000 fans in 13 cities, an impressive figure for any band. But in Great Britain, Oasis isn’t just any band – it is the band. To get a perspective of how popular the musicians are in their homeland, check this out: Two weeks ago, the five-man group from Manchester performed two nights at England’s Knebworth Park to more than 250,000 people. It was the largest audience for any single band in Britain.

With the momentum that Oasis had after the success of “Wonderwall,” it seemed natural that the group’s next conquest would be the United States. But while Anglophiles and Britpop fans quickly succombed to the band’s intoxicating fury of rock ‘n’ roll songs, Oasis is a “medium” band here compared to America’s behemoths the Smashing Pumpkins and Pearl Jam. Never mind that Oasis’ catchy hooks and sweet guitar riffs dance circles around those groups’ melodies.

The fact is, Americans haven’t warmed up to any Oasis single since “Wonderwall,” even though “Champagne Supernova,” “Don’t Look Back in Anger” and “Morning Glory” have been played ad nauseum on alternative radio and MTV.

Part of this may be cultural. Though the Pumpkins are doing well in England, Pearl Jam elicits little more than a yawn there.

Not surprisingly, London’s Bush, which sounds basically like warmed over Pearl Jam, devoted almost all of its time touring America rather than staying in its grunge-o-phobic homeland where it is not played and worse, despised. Or it could just be that few bands of any nationality achieve the type of popularity that the Pumpkins receive here and that Oasis gets in England.

But Oasis is hardly a failure. “What’s the Story (Morning Glory)?” sold more than 3 million copies here, and the interest in that LP renewed interest in “Definitely Maybe,” which went gold. So don’t bet against Oasis’ making it big in the U.S. Unlike other talented, highly hyped U.K. bands such as Teenage Fanclub and Suede, Oasis has one quality that differentiates them. The musicians are tenacious about achieving world domination, and they’re patient enough to keep coming back here until we adore them, too.

“It takes time to build up a base around the world,” Noel Gallagher said, sipping a cup of hot tea. “There’s only so many countries you can visit in a year. Obviously in England it’s easy (to get popular) because it’s so small.”

If not the best in the world, Oasis certainly is right up there. Slagged by some critics for admiring the Beatles too much, right down to the mop-top hairdos, Oasis is one of the few bands that actually has the talent to back up its bravado. Noel Gallagher is a prolific songwriter who cranks out glorious, well-crafted pop songs.

In Britain, the band releases non-album singles quarterly that are as strong as the LP tracks. Though Gallagher is uncharacteristically modest about his songwriting abilities, he has a knack for whipping up tunes that capture the essence of being young and alive.

Gallagher has a deep, pleasant voice that he showcases on “Don’t Look Back in Anger” and in acoustic interludes at their live shows, but it’s Liam who possesses the more seductive, mesmerizing vocals. The younger Gallagher is an alluring singer whose nasal voice is part John Lennon, part Johnny Rotten. He sings Noel’s songs, giving the lush melodies and hooks a swaggering edge.

Even when he wasn’t a working musician, Noel had big dreams. In the late ’80s, he auditioned for Manchester’s Inspiral Carpets to be their singer. They passed, but hired him as a guitar tech. He pushed his ego aside and took the job, traveling the world with the group for almost four years. He kept writing songs, but no one took a roadie’s songs seriously.

In 1991, while Noel was on the road with the Carpets, Liam had formed a rock band with some of his friends. Noel thought the band had potential, but found their material to be inferior. He agreed to join the group if the others agreed to play only his originals.

Noel, who had saved enough money to buy equipment for the group, became an official member of Oasis the following year. Shortly thereafter, Noel took over Liam’s role as leader of the band.

Despite their public arguments, Liam has always acknowledged his brother’s excellence as a songwriter, proclaiming that Noel’s writing is comparable to John Lennon’s work. And Noel has expressed awe at the way Liam captures the poignancy of “Wonderwall.”

But if that’s the case, then why does Noel sing their most popular song at their shows?

“It’s really difficult to do `Wonderwall’ as a group because of the strings, and there’s not many electric guitars on it,” he explained. “So we decided we were going to do it acoustically and that I was going to do it. Liam’s got a really strong voice that sounds great with a full band. But he’ll be the first to admit that with an acoustic guitar, he’s a bit too loud to sing that song.”

Asked if he ever wanted to take over as full-time singer, Gallagher said, “We have a singer – a really good one. I never wanted to be an out-and-out front man. I don’t know if I could handle it.”

Changing his mind, he added, “No, I could probably handle it, because I write the songs and arrange them and produce them. . . . But I don’t need the hassle of being the singer as well.”

At the Aragon soundcheck, it was Liam who was intent on hassling Noel. The moody singer jumped off the stage and meandered around the venue playing with a worn soccer ball. Looking at Noel, who was still rehearsing, Gallagher took aim and expertly kicked the ball to or, depending on who you asked, at his brother. Noel stopped the ball with his right foot, but wouldn’t surrender it to Liam until the song was over.

Half an hour later, when Noel was doing an interview backstage, Liam – who had told his publicist that he wouldn’t talk to the press – walked up to his brother and sarcastically said, “How nice of you to take care of all the interviews without telling the rest of us. It’s so kind of you to become the spokesman for the band.”

Noel calmly replied, “You can do it if you want to.”

As Liam slowly walked away, Noel launched into a stream of salty adjectives about his brother. The nicest thing he said about the singer was, “He’s a nut. ”

But all was forgiven during their concert. The brothers played well off each other, and reveled in a childish prank. Near the end of their last song, a dead-on cover of the Beatles’ “I Am the Walrus,” they walked off the stage, only to return a few moments later to tickle Arthurs and McGuigan. The Brothers Gallagher had made up.

“By now you should’ve somehow realized what you gotta do…” I love #Wonderwall. I’m a big Beatles fan, too, and George Harrison had that album out called, “Wonderwall,” which is where Oasis got their song title. 🙂

Ha! Some are more fun than others. It’s really fun when you get to talk to them over a period of time. The first time I interviewed Jackie Chan, an interpreter was there to assist him with his English. A couple years later, he was completely fluent in English and asking me about various Korean dishes. (Watch your heads, folks! I’m namedropping all over the place!)

Could you be a u cooler, I was more blur than oasis but since I never met anyone from blur I would take anyone from oasis, holy crap this is awesome, now I Justyna have to meet you to link myself to ringo and Liam and therefore link myself to my two favorite bands of all times ever the Beatles and blur!!!

I love Blur, too. Their “Song 2” is a fave. If I worked out, that’d be my soundtrack to make me run/exercise faster and harder! 🙂 I’ve interviewed Damon Albarn and Alex James of Blur etc. as well. Blur and Oasis had no love for each other. I thought it was kind of made up in the media, but they talked smack about each other. It was kind of funny! The one thing they both had in common is they both hated Gavin Rossdale of Bush (who I also interviewed).

Stop it!!! You did not!!! Okay now you have to meet me and tell me all about it, I was conditioned to “hate” oasis like a real fan should but I never did and listened to their music, just like all the other britpop music, did they also hate pulp and manic street preachers and a billion others..?

Also, all of the followers of @hennablossom should know that I took her to a few concerts when she was a teenager. I know I have photos squirreled away of her with various members of Oasis and the aforementioned and much maligned Gavin Rossdale. Also, there’s a photo floating around of her with #nsync. 🙂

God bless it lady! You are amazing!! I love not only your photos, but your captions too. You’ve already done so many amazingly unique and wonderful things in your life,all while being a mama!! You’re definitely someone I aspire to meet one day!! You and @hennablossom!

Thank you, ma’am! 🙂 I’m grateful to have led a good, fun life that has also been fulfilling (that’s not the meeting rock stars part! Ha!). One of my greatest joys is the family I have. @hennablossom is my first niece. It was her birth that triggered my desire to really, really want to be a mom one day, too. I am so proud of her and my other nieces and nephews. They are truly some of the brightest and best, and I am so proud to be their aunt. 🙂